南海北部陆缘裂后异常沉降与下地壳流的关系的动力学数值模拟研究

项目名称： 南海北部陆缘裂后异常沉降与下地壳流的关系的动力学数值模拟研究

项目编号： No.41506063

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 天文学、地球科学

项目作者： 王晓芳

作者单位： 中国科学院南海海洋研究所

项目金额： 22万元

中文摘要： 南海北部陆缘拉张演化过程中出现了裂后异常构造沉降现象，下地壳流经常被用来解释地壳随深度的差异拉张现象，但下地壳是否发育下地壳流一直是目前人们所关注的焦点。近年来已有一些研究成果，但前人的工作是偏于定性、半定量或者为运动学模型的基础上的。本项目针对南海北部陆缘是否发育下地壳流进行定量的动力学数值模拟研究。选择南海北部陆缘，横穿华南大陆地块、大陆向海洋过渡带直到南海海盆（包括珠江口盆地和北部湾盆地及其凹陷带）为研究对象，建立结合地表过程（包括地表侵蚀、盆地沉积过程）和张裂过程的动力学数值模型，通过数值模拟分析，研究南海北部大陆边缘在新生代构造演化过程中是否具备发育下地壳流的条件。如果发育下地壳流，发生的时间和流动的方向如何？从而探索被动大陆边缘海成因和岩石圈演化的动力学机制，揭示南海北部大陆张裂到南海海底扩张的重要信息。并为地质构造、地震危险性评估和油气与水合物资源的开发利用提供可靠的依

中文关键词： 南海北部陆缘；；异常沉降；动力学数值模拟；下地壳流

英文摘要： There is anomalous tectonic subsidence in the tension of the north continental margin of South China Sea. Lower crust flow theory is often used to explain the phenomenon of depth-dependent stretching, but the lower crust flow theory is still controversial. Although there are some research results recently, most of which are quantified or half-quantified or on the base of the kinematics model. The aim of this project is to quantitatively simulate the problem that is the relationship between lower crustal flow and anomalous post-rift subsidence along the northern South China Sea caused by the differences between upper and lower crust. The project selects continental marginal along the northern South China Sea , the continental blocks across the South China, continent to ocean transition zone to ocean basin of South China Sea(including Pearl River Mouth Basin and Beibuwan Basin and depression belt) as the study objects, then build the dynamical numerical model combined the earth' s surface process (mountain erosion,basin deposition process) and rifting process, through the numerical analysis,we study whether the continental marginal along the northern South China Sea is possible to have the condition of lower crustal flow during the rifting process in new era. If possible,what is the time or flow direction of lower crustal flow? The purpose of this work is to explore the cause of formation of passive continental marginal sea and the evolution of the lithosphere , it can provide important information about the process of from continental splitting to seafloor spreading and reliable basis to geological structure, seismic hazard assessment and resource development and utilization of oil and gas and hydrate.

英文关键词： Northern margin of South China ;Anomalous subsiden;Dynamics numerical simulation ;The lower crustal flow